Search

Background: Recent evidence suggests an elevated risk of cognitive impairment and dementia in individuals with atrial fibrillation (AF), irrespective of stroke occurrence. AF, known to reduce brain perfusion, particularly through silent cerebral ischemia, underscores the intricate relationship between cardiac and cerebral health. The heart plays a crucial role in supporting normal brain function, and rhythm control, a standard AF treatment, has demonstrated enhancements in brain perfusion. This systematic review aimed to examine published data concerning the influence of rhythm control on brain perfusion in patients with atrial fibrillation. Methods: A systematic search for relevant studies was carried out in Scopus, PubMed, Cochrane Reviews, ProQuest, and EBSCOhost, spanning from their inception until April 30, 2023. Studies that specifically examined brain perfusion following any form of rhythm control in atrial fibrillation were included in the review. Results: The review encompassed 10 studies involving 436 participants. Among these, six utilized electrical cardioversion for rhythm control. The majority (8 out of 10) demonstrated that restoring sinus rhythm markedly enhances brain perfusion. In one of the two remaining studies, notable improvement was observed specifically in a region closely linked to cognition. Additionally, both studies reporting data on the Mini-Mental State Examination (MMSE) showed a consistent and significant increase in scores following rhythm control. Conclusion: Successful rhythm control in AF emerges as a significant contributor to enhanced brain perfusion, suggesting a potential therapeutic avenue for reducing cognitive impairment incidence. However, further validation through larger prospective studies and randomized trials is warranted. [ABSTRACT FROM AUTHOR]

The relationship between (a) the structure and composition of the landscape around an individual's home and (b) environmental perceptions and health outcomes has been well demonstrated (eg the value of vegetation cover to well‐being). Few studies, however, have examined how multiple landscape features (eg vegetation and water cover) relate to perceptions of multiple environmental problems (eg air or water quality) and whether those relationships hold over time. We utilized a long‐term dataset of geolocated telephone surveys in Baltimore, Maryland, to identify relationships between residents' perceptions of environmental problems and nearby landcover. Residents of neighborhoods with more vegetation or located closer to water were less likely to perceive environmental problems. Water quality was one exception to this trend, in that people were more likely to perceive water‐quality problems when nearby water cover was greater. These trends endured over time, suggesting that these relationships are stable and therefore useful for informing policy aimed at minimizing perceived environmental problems. [ABSTRACT FROM AUTHOR]

Given the large and increasing amount of urban, suburban, and exurban land use on Earth, there is a need to accurately assess net primary productivity (NPP) of urban ecosystems. However, the heterogeneous and dynamic urban mosaic presents challenges to the measurement of NPP, creating landscapes that may appear more similar to a savanna than to the native landscape replaced. Studies of urban biomass have tended to focus on one type of vegetation (e.g., lawns or trees). Yet a focus on the ecology of the city should include the entire urban ecosystem rather than the separate investigation of its parts. Furthermore, few studies have attempted to measure urban aboveground NPP (ANPP) using field‐based methods. Most studies project growth rates from measurements of tree diameter to estimate annual ANPP or use remote sensing approaches. In addition, field‐based methods for measuring NPP do not address any special considerations for adapting such field methods to urban landscapes. Frequent planting and partial or complete removal of herbaceous and woody plants can make it difficult to accurately quantify increments and losses of plant biomass throughout an urban landscape. In this study, we review how ANPP of urban landscapes can be estimated based on field measurements, highlighting the challenges specific to urban areas. We then estimated ANPP of woody and herbaceous vegetation over a 15‐year period for Baltimore, MD, USA using a combination of plot‐based field data and published values from the literature. Baltimore's citywide ANPP was estimated to be 355.8 g m−2, a result that we then put into context through comparison with other North American Long‐Term Ecological Research (LTER) sites and mean annual precipitation. We found our estimate of Baltimore citywide ANPP to be only approximately half as much (or less) than ANPP at forested LTER sites of the eastern United States, and more comparable to grassland, oldfield, desert, or boreal forest ANPP. We also found that Baltimore had low productivity for its level of precipitation. We conclude with a discussion of the significance of accurate assessment of primary productivity of urban ecosystems and critical future research needs. [ABSTRACT FROM AUTHOR]

Though concerns about the proliferation of synthetic chemicals - including pesticides - gave rise to the modern environmental movement in the early 1960s, synthetic chemical pollution has not been included in most analyses of global change. We examined the rate of change in the production and variety of pesticides, pharmaceuticals, and other synthetic chemicals over the past four decades. We compared these rates to those for well-recognized drivers of global change such as rising atmospheric CO2 concentrations, nutrient pollution, habitat destruction, and biodiversity loss. Our analysis showed that increases in synthetic chemical production and diversification, particularly within the developing world, outpaced these other agents of global change. Despite these trends, mainstream ecological journals, ecological meetings, and ecological funding through the US National Science Foundation devote less than 2% of their journal pages, meeting talks, and science funding, respectively, to the study of synthetic chemicals. [ABSTRACT FROM AUTHOR]

As part of a 7-year lifecycle monitoring study, electroshocking was used to capture and characterize a small population of federally listed endangered southern California steelheadOncorhynchus mykissin Topanga Creek, Los Angeles, California. Electroshocking is a tool widely used to study fish populations, despite its potential behavioral and physical effects on individuals. We examined rates of external hemorrhaging (i.e., branding) and its effect on growth rates and survival of recaptured individuals. Rates of branding were low (0–3%) during most November events from 2008 to 2014, but higher during all March events (8–23%) and during the November 2011 event (13%). Overall, 5% of the total captured individuals exhibited branding. Growth rates (mm/d) of individuals recaptured after branding were not significantly different, but on average were 9% lower than average daily growth rates for individuals in the same size-class captured and recaptured in the same time periods. In general, larger fish were more likely to be branded than were smaller fish (P< 0.0001). Although 69% of brandings occurred in pool habitats, which tend to be larger and deeper than other habitats, branding was not significantly more likely to occur in any habitat type (P= 0.13) or in any substrate type (P= 0.16), and mean or maximum depth of habitat was not related to the rate of branding. The population-level effects associated with branding remain unclear. Although important information has been obtained through the use of electroshocking, the cumulative effects of electroshocking-induced injuries to this endangered species need to be considered. Received March 2, 2015; accepted March 27, 2016 Published online July 19, 2016 [ABSTRACT FROM AUTHOR]

River regulation may mediate the interactions among native and nonnative species, potentially favoring nonnative species and contributing to the decline of native populations. We examined food resource use and diet overlap among small-bodied fishes in the Grand Canyon section of the Colorado River as a first step in evaluating potential resource competition. We compared the diets of the predominant small-bodied fishes (native Speckled DaceRhinichthys osculus, juvenile Flannelmouth SuckerCatostomus latipinnis, and juvenile Bluehead SuckerC. discobolus, and nonnative Fathead MinnowPimephales promelas) across seasons at four sites downstream of Glen Canyon Dam using nonmetric multidimensional scaling and Schoener's similarity index. The diets of these fishes included diatoms, amorphous detritus, aquatic invertebrates (especially simuliid and chironomid larvae), terrestrial invertebrates, and terrestrial vegetation. Diets varied with season and were affected by high turbidity. Fish consumed more amorphous detritus and terrestrial vegetation during the summer monsoon season (July–September), when turbidity was higher. The diets of all species overlapped, but there was large variation in the degree of overlap. The diets of juvenile suckers and Fathead Minnows were most similar, while Speckled Dace had relatively distinct diets. The differences took the form of higher proportions of diatoms and amorphous detritus in the diets of Bluehead Suckers and Fathead Minnows and higher proportions of simuliids and chironomids in those of Speckled Dace. If food resources are or become limiting, diet overlap suggests that competition may occur among native and nonnative species, which could have implications for the population dynamics of these fishes and for the management of the Colorado River ecosystem in Grand Canyon. Received September 4, 2013; accepted February 11, 2014 [ABSTRACT FROM PUBLISHER]

Pharmaceutical and personal care products are ubiquitous in surface waters but their effects on aquatic biofilms and associated ecosystem properties are not well understood. We measured in situ responses of stream biofilms to six common pharmaceutical compounds (caffeine, cimetidine, ciprofloxacin, diphenhydramine, metformin, ranitidine, and a mixture of each) by deploying pharmaceutical‐diffusing substrates in streams in Indiana, Maryland, and New York. Results were consistent across seasons and geographic locations. On average, algal biomass was suppressed by 22%, 4%, 22%, and 18% relative to controls by caffeine, ciprofloxacin, diphenhydramine, and the mixed treatment, respectively. Biofilm respiration was significantly suppressed by caffeine (53%), cimetidine (51%), ciprofloxacin (91%), diphenhydramine (63%), and the mixed treatment (40%). In autumn in New York, photosynthesis was also significantly suppressed by diphenhydramine (99%) and the mixed treatment (88%). Pyrosequencing of 16S rRNA genes was used to examine the effects of caffeine and diphenhydramine on biofilm bacterial community composition at the three sites. Relative to the controls, diphenhydramine exposure significantly altered bacterial community composition and resulted in significant relative increases in Pseudomonas sp. and decreases in Flavobacterium sp. in all three streams. These ubiquitous pharmaceuticals, alone or in combination, influenced stream biofilms, which could have consequences for higher trophic levels and important ecosystem processes. [ABSTRACT FROM AUTHOR]

The article presents a study which quantifies organic matter flows in the food web below Glen Canyon Dam in Arizona after an experimental controlled flood in March 2008. It reveals the decline of invertebrate biomass after the flood. It illustrates the value of detailed food web analysis to which dam management may alter production and species interactions in food webs of rivers. It suggests that controlled floods increase production of nonnative rainbow trout.

The article examines the impact of Bt maize leaf detritus on aquatic invertebrates in headwater streams. It was found that the insect Lepidostoma liba grows slower when it is fed with Bt maize compared to non-Bt maize. There is no significant difference found in total abundance or biomass of benthic macroinvertebrate abundance between Bt and non-Bt streams. Shannon diversity in both streams is low while highly tolerant taxa is dominant in Bt and non-Bt streams.

Environmental and ecological research has long been characterized as operating along a continuum, with "basic" - representing "investigator-initiated" research - at one end and "applied" - representing "mission-initiated" research - at the other. While federal agency science programs ideally occupy points along this continuum, the resulting science has not always been relevant to solving environmental problems. Here, we suggest that environmental problem-solving by federal agencies has been less effective than it might have been, because of a need for more effective, long-term strategic planning, cooperation across agencies, and incentives for scientists to participate in policy development and implementation. We make suggestions about what federal agencies can do to improve the integration of science, policy, and natural resource management. First, we refer to agency examples, using regulatory (acid deposition) and land management (national forest) issues to illustrate how environmental research intersects with policy development and its implementation. Second, we discuss the barriers that inhibit the application of scientific knowledge in developing and implementing policy - from the perspective of a federal agency and of an individual scientist. Finally, we generate a series of specific recommendations, targeted at federal agencies, individual scientists, and decision makers. [ABSTRACT FROM AUTHOR]

- A study was made of the diagnostic reliability of renal ultrasound with a diuretic in the evaluation of upper tract obstruction. The test comprised an initial renal ultrasound examination followed by the intravenous injection of 250 ml physiological saline with 40 mg frusemide; further ultrasound scans were carried out from 5 to 150 minutes later. A total of 67 patients was studied and the results were compared with those of diuretic intravenous urography, diuretic renography and, in some cases, the Whitaker test. Dynamic ultrasound with a diuretic showed a sensitivity of 94%, specificity of 94%, positive predictive value of 91% (obstructive), negative predictive value of 96% (non-obstruction) and a total diagnostic capacity of 94%. [ABSTRACT FROM AUTHOR]

The continually increasing global population residing in urban landscapes impacts numerous ecosystem functions and services provided by urban streams. Urban stream restoration is often employed to offset these impacts and conserve or enhance the various functions and services these streams provide. Despite the assumption that "if you build it, [the function] will come," current understanding of the effects of urban stream restoration on stream ecosystem functions are based on short term studies that may not capture variation in restoration effectiveness over time. We quantified the impact of stream restoration on nutrient and energy dynamics of urban streams by studying 10 urban stream reaches (five restored, five unrestored) in the Baltimore, Maryland, USA, region over a two‐year period. We measured gross primary production (GPP) and ecosystem respiration (ER) at the whole‐stream scale continuously throughout the study and nitrate (NO3−‐N) spiraling rates seasonally (spring, summer, autumn) across all reaches. There was no significant restoration effect on NO3−‐N spiraling across reaches. However, there was a significant canopy cover effect on NO3−‐N spiraling, and directly comparing paired sets of unrestored‐restored reaches showed that restoration does affect NO3−‐N spiraling after accounting for other environmental variation. Furthermore, there was a change in GPP : ER seasonality, with restored and open‐canopied reaches exhibiting higher GPP : ER during summer. The restoration effect, though, appears contingent upon altered canopy cover, which is likely to be a temporary effect of restoration and is a driver of multiple ecosystem services, e.g., habitat, riparian nutrient processing. Our results suggest that decision‐making about stream restoration, including evaluations of nutrient benefits, clearly needs to consider spatial and temporal dynamics of canopy cover and trade‐offs among multiple ecosystem services. [ABSTRACT FROM AUTHOR]